(a) Field of the Invention
The present invention relates to a structure for mounting an air cleaner near an engine.
(b) Description of the Prior Art
It is sometimes difficult to mount an air cleaner on an engine. For example, in an engine with a fuel injection system, the fuel injector system and an air duct are mounted on the engine and the air cleaner is mounted on the vehicle body. The air cleaner and duct which introduces fresh air to it are mounted on the vehicle body and engine respectively using a rubber mounting and are connected through a rubber hose, as disclosed by the Japanese Utility Model Laying Open Gazette No. 63-14428.
In another application, an air cleaner is arranged in the empty space above the transmission to reduce the size required for the engine compartment, as disclosed by the Japanese Utility Model Publication Gazette No. 61-28041. Here, engine vibration is prevented from being transferred to the vehicle body because the air cleaner is mounted on the engine. However, the air cleaner receives vibration from the engine and when this vibration frequency coincides with the natural frequency of the air cleaner, the air cleaner resonates, possibly reducing the reliability of the air cleaner.
In a specific example, an air flow meter used to control engine operation is provided on the air cleaner. Where this air flow meter is a hot wire type system, the fine hot wire could break due to the vibration of the engine. In an air cleaner made of a resin, the air cleaner resonates when the engine vibration is approximately 5000 rpm and this could cause the hot wire to break.
The configuration of the air cleaner can be changed, but this only shifts the resonance point and does not substantially solve the air cleaner resonance problem.